Stoker motor control



May 4, 1937. J. F. TURNER ET AL STOKER MOTOR CONTROL Filed Sept. 6, 1934 4 Sheets-Sheet l fifllllllllJ y 1937- J. F. TURN-ER ET AL 2,079,135

STQKER MOTOR CONTROL Filed Sept/6, 1934 4 Sheets-Sheet 2 May'4, 1937. J.- F. TURNER ET AL STOKER MOTOR CONTROL 4 Sheets-Sheet 5 Filed Sept. 6, 1934 ay 4, 1931- J. F. TURNE LET AL 2,079, 35

' STOKER MOTOR CONTROL Filed Sept. 6; 1934 4 SheetsSheet 4 Patented -May 4," 1937 PATENT OFFICE 2,079,135 STOKER MOTOR CONTROL James F. Turner and Christian P. Breidenbaugli, Baltimore, Md., assignors to Flynn" & Emrich Company, Baltimore, Md., a corporation of Maryland Application Scpte nber"6,-1934,Serial No. 742,973 19 Claims. 01. 60-52) The invention relates to fuel feeding, the invention having been developed in connection with the feeding of fuel to an underfeed stoker. Such stokers are provided withxa retort into which 5 the fuel is forced by means of a ram. This re- 7 tort is in accordance with the established practice associated with inclined grates which slope downwardly from twyer blocks at the top of the retort which is open. The fuel as itis forced into the retort by the rammises upwardly and flows over the twyer blocks, being heated in the retort. and burned as it passes down the incline.

The device 01 the invention has been most generally applied to small plants though it is [5 capable of use on the larger plants and .the device of the invention, though it is particularly adapted for use with underfeed stokers, may be applied to other types of stokers and to fuel feeding in general. In the operation of underfeed stokers, one of the important difliculties encountered is incident to the cramping and jamming of coal or other fuel in front of the ram, either in the retort where a certain amount of-coking takesplace in addition to the wedging and jamming of the fuel as it is advanced or in the rampassage where the feeding of the fuel by pressure from the rear also results in wedging and jamming of the particles or lumps of fuel. 30 Whileit is possible to provide continuously, suiiicient power to overcome any resistance which may be offered, the consumption of power under these circumstances is excessive and'the expense too great; particularly in the operation of small plants. Under any circumstances there is an impprtant loss of economy in feeding coked fuel in this way. v When a source of power is employed which is commensurate with the ordinary consumption of power by the motor, the presentation of an excessive: resistance to the operation of the ram due to cramping or coking of the fuel not infrequently stops the operation of the motor entirely so that in the absence of close supervision the fuel feed being discontinued. the fire burns low or goes out, the steam pressure is lost and the operation of the plant ceases. r In the plant to which the invention is applied the ram is operated by means of a fluid pressure motor, generally. known as a hydraulic motor, the operating pressure being obtained by means of a relatively small pump which to the best advantage is electrically driven, though it may be driven from other sources of power. The system plied to the same are correspondingly increased loaded are encountered, when the building up of pressure is repeated.

'which increases the power of the motor and the tice of the invention is several-times the normal illustrated provides for continuous circulation,

i. e., the hydraulic fluid is fed to the motor under pressure by the pump and discharged from the motor into a chamber from which it passes to the intake or suction side of the pump. This 5 arrangement is not, however, essential to the use of the invention in all the forms contemplated.

The object of the invention is to provide for the normal operation of the motor at a relatively low pressure which places a comparatively small 10 burden upon the pump and the source of power as an electric motor from which the pump is driven, the pressure of the fluid being automatically built up by the pump when an obstruction is encountered by the ram, the working pressure of the fluid supplied 'to the hydraulic motor being automatlcallyincreased, the power and piston thrust generated by the hydraulic motor and apuntil the obstruction or resistance is overcome 20 when the pressure is immediately dropped to normal and operation of the motor and pump at normal pressure continues until other, excess resistances whereby the hydraulic moto'r is over- In accordance with the preferred form of the invention illustrated, this object is attained bybypassing a portion of the hydraulic fluid pumped which is returned to the intake of the pump without entering the hydraulic motor. This prevents the building up of pressure in the motor beyond a predetermined point and hence prevents a consumption of power beyond the predetermined normal untii an excess'resistance or overload is encountered when the bypass is automatically closed, the pump builds up imthe sup ply of hydraulic fluid to the motor a pressure piston thrust applied to the fluid until it overcomes the resistance. This operation is limited by a'predetermined maximum pressure generated by the pump which in accordance with the pracwith a low consumption of power adapted to fuel feeding under normal conditions and only in relatively rare instances is it necessary to build up the pressure of the hydraulic motor using an increased consumption of power for a few seconds only until an excessive resistance is overcome. In this way a very considerable economy is effected and, more important than this, an absolutely dependable operation of the fuel feed is attained.

In the accompanying drawings we have illustrated so much of a stoker motor of the hydraulic type, a ram driven thereby, a ram passage, a fuel hopper, a pump and an electric motor for driving the pump to which the device of the invention is applied, as is necessary to a. full comprehension of the manner of constructing, operating, applying and using the invention.

In the drawings:-

Figure 1 is a side elevation of a hydraulic motor and a ram operated thereby together with a pump for supplying hydraulic fluid under pressure to the motor and an electric motor for driving the pump.

Figure 2 is a section on the axis of the relief valve of the invention, also showing its connection to the pump pressure passage.

Figure 3 is a section on the line 3, 3 in Figure 2.

Figure 4 is a section on the line 4, 4 in Figure 6, through the hydraulic motor valve chamber and the pilot valve chamber including the valve passages leading from the valve casing to and from ing the pilot valve and seat and also showing the I throttle valve.

Figure 7 is a section on the line I, l in Figure 6, showing the throttle valve, the pump passage and the hydraulic motor valve chamber.

Referring to the drawings by numerals, each of which is used to indicate the same' or similar parts in the different figures, the construction shown comprises a hydraulic or equivalent motor with its cylinder 2' and piston 2, connected by a piston rod 3 to a fuel feeding ram 4 which operates in a ram passage 5 in alignment with the hydraulic motor cylinder. The construction also includes a hydraulic fluid pump 6, which is driven by means of an electric motor I through and by a belt 8 which engages a pulley 9 on the shaft of the electric motor driving a pulley 9' which operates the pump to provide a suitable supply of hydraulic fluid under pressure to the motor.

The hydraulic motor cylinder 1 is connected at each end to a valve casing l0 containing a piston or other suitable valve H, such connecttion being shown in the form of intake and exhaust passages I2 and I4. The passages i 2 and I4 terminate in the valve casing to in intake and exhaust ports l5, l6 and there is an exhaust port" which in the form of the invention shown is connected to the exhaust passage l8 leading to the low pressure or suction chamber 20 from which hydraulic fluid is supplied to the pump. which has an intake 20 in chamber 20. The fluid under pressure from the pump 6 is led by way of pressure passage 2| to the pressure chamber 22 of the valve casing III to be delivered by way of the ports l5, l6 and the passages l2. l4 to the respective ends of the hydraulic motor cylinder. This distribution of the hydraulic fluid underpressure is performed under the control of the slide valve 24 which in the form of the invention shown is operated by the valve piston l manual control of the stoker.

This piston II in the form shown is a double ended piston operated from both ends by hydraulic fluid in both cylinder ends, being controlled by the pilot valve 25. The pressure chamber 22 is illustrated fragmentarily in section in Figures 4 and '7 in connection with the adjacent end of the pressure passage 2|, 'to which it is connected by a throttle valve seat 26 controlled by a throttle valve 21 shown as operated by a screw stem 28. vThe valve 21 is secured to the stem 28, the threaded portion 29 of the stem 28 being engaged with a screw plug 30 seated in a suitable opening in the wall of the passage 2|, the plug 30 having combined therewith a suitable packing gland 3l. The. valve stem 28 is shown as provided with a circular graduated head or handle 32 secured to the outer end of the stem 28, the graduations being indicated by reference character 33. These graduations cooperate with a suitable stationary pointer 34 secured 'to the valve casing Ill.

The throttle valve 21 is used to determine by throttling the normal pressure of the motor fluid in the chamber 22. It may be operated and located in any convenient manner, the above details being merely the preferred form.

A similar type of cylinder valve controlling a hydraulic motor is illustrated in our Patent No. 2,004,558 the operation of the cylinder valve being in turn controlled by a pilot valve which is identical with the pilot valve 25 of the present construction. The pilot valve assembly comprises a casing 35 containing a valve seat 36 and a pilot slide valve 31 cooperating with the seat and actuated by means of valve rods projecting at one end of the valve casing at 38 and at the other end of the valve casing at 39, said rods being threaded at their inner ends into the corresponding ends of a valve carrier 40 in the pilot valve chamber 4| of the pilot valve casing 35. The rod 33 projects at one end through a packing gland 42 and the rod 39 projects at one end through a. packing gland 43, the rod 39 having secured to its outer end a handle 44 .for use in the manual operation of the pilot valve and the The motor I is automatically controlled by means of a lever mechanism like that of our copending application No. 649,558, shown in plan in Figure 5 of said application. This mechanism comprises a horizo'ntally arranged lever 50 at the side of the ram and extending in the general direction of the ram 4. This is secured at.its center by means of a set screw 49" tothe lower end of an upright shaft 49 which is seated in a boss projecting upwardly from the lever 50. This shaft rotates in suitable bearings 41 in the main casting containing the ram passage, motor cylinder, etc. The shaft 49 carries at its upper end a lever 45 which projects in a horizontal plane at right angles to the lever 50. The lever 45 which oscillates with the shaft has jaws 46 which straddle the rod 38 between the stops or abutments 48 on said rod. Lever 50 carries followers 50, 50" which are in the path of the cam member 49' which projects from the side of the ram 4. At each end of the ram stroke the contact of the cam member with the followers 50, 50 at the ends of the lever 50 serves to swing the lever 50, likewise swinging or rocking the lever 45, moving the rod 38 by contact of the jaws 46 with the stops or abutments 48, shifting the valve 31 as in the previous construction described in the copending application. The operation of this construction being a mere incident to the operation of a well known control valve, is nopart of the present invention. The shifting -of the valve 31 operates the piston ll, shifting the hydraulic motor valve 24, admitting hydraulic fluid to the corresponding end of the cylinder 2' and effecting a stroke of themotor, when the pilot valve is again operated and another stroke of the motor is effected in due course as above. The power and hence the speed of the motor is controlled as hereinafter described, the mechanism for the purpose being the important subject of the invention.

The piston I of the hydraulic motor slide-valve 24 which controls the supply of hydraulic fluid under pressure to the hydraulic motor cylinder 2" and the exhaust therefrom is controlled bythe pilot slide 'valve 31 which slides on the pilot valve seat shown in top plan in Figure 5. This seat contains an inlet passage 5| which may be otherwise suitably located. By way of this port fluid under pressure is supplied to the pilot valve chamber 4|, the passage 5| being connected to thepressure chamber 22 of the cylinder valve casingby a passage 52.

nected by an exhaust passage 54 to the motor exhaust l6 and with end exhaust ports 55, 56 on each side of the exhaust port 54 in the direction These ports 55 and 56 are provided with pressure'ports 60, 6|, spaced laterally from the center exhaust port 53 to be covered and uncovered by the pilot slide valve 31 best illustrated in plan in Figure 6 and shown in section in Figure 4. These ports 60 and 6| are uncovered alternately and when either port is uncovered the corresponding. hydraulic motor valve cylinder 59 is connected to a supply of hy- 'vide draulic fluid under pressure led to the pilot valve chamber 4| by way of the passages 5| and 52 from the cylinder valve chamber 22. To effect the alternative closing and opening of the pressure ports 60, 6|, the pilot slide valve 31 is provided with staggered and lateral extensions 62 and 63, and to provide for the alternate connection of the end exhaust ports. 51 and 56, leading from the head ends'of valve cylinders 59 to the central exhaust port'53, the slide valve 31 is prowith grooves or passages 64 and 65 in its bott m surfaces. The hydraulic motor valve casing I is also provided with inlet or pressure passages 66, 61 connected to the head ends of the a respective hydraulic motor valve cylinders 59 and-to thepressure ports 60, 6|, in the pilot valve seat by passages 60', 6| in said seat continuous with-the corresponding inlet or pressure passages 66, 61. I As the motor valve 26, is shifted by the operating of the pistons H in the cylinders 59 under the control of the pilot valve 31, the ports and I6 are alternately opened to the pressure in chamber 22, and connected to exhaust passage 1' which in the form shown leads to pump suction or supply chamber 20 and may lead to any suitable exhaust.

The relief valve in combination with the motor and a supply of fluid under pressure to operate the same with throttling means between the motor and the source of supply, the manner of connectingthe relief valve to the hydraulic fluid pressure line on both sides of the throttling means and the details of the relief valve assembly con- The pilot valve seat 36 1 is provided with a center exhaust port 53 constitute the novel subject matter of the invention.

The relief valve assembly 10 in the form shown comprises' a seat member 1| connected to the pressure passage 2|.which receives fluid under pressure directly from the pump. This seat member 1| has a relief passage 12 connected to the passage 2| at the outer end of which passage is a seat 13. Cooperating with this seat in the form of the invention shown is a ball valve 14 forwhich any suitable type of nonreturn valve may be substituted. At the sides of the valve seat are discharge openings 15 which in the form of the invention shown lead to the low pressure or suction chamber in which the seat member 1| is located. This seat member 1| as illustrated is extended beyond the seat 13 in the form of'a tubular spring casing 16 in which is 'located the relief valve spring 11 which tends to hold the check valve or nonret'urn valve ball 14 in contact with the seat 13. This spring engages at one end the disk 19 of valve cap 18 which disk is concaved on one side to flt the ball and provided on the other side with a projecting stud 80 which is enclosed in the end coils of the spring 11. The spring 11 bears at the end opposite to the stud 60 and disk 19 against a plunger 8| which slides in the tubular spring casing 16, thus determining the tension of the spring and thepressure on the ball which tends to maintain it closed againstthe pressure .of the hydraulic-fluid in the passage 2|. The plunger 8| iscar'ried by a pin 82 which extends to the left in Figure 2 from the plunger 8|, being engaged at its extreme end by an adjusting screw 83 which is held in adjusted position by a lock nut 84, the screw 83 being threaded into a suitable tapped hole in head. N18, to be described.

This head is stationary. Thus, the pressure at which a portion of the hydraulic fluid is dis charged through the relief valve seat 13 and/or by-passed around the throttle, is regulated. Under normal load and pressure the valve is open, the spring being adjusted and the excess fluid pumped at this pressure, the amount of which is a function of the resistance offered to the operation' of the motor due to the resistance of the ram, and of the power applied to the pump, is discharged and/or by-passed as hereinafter described. By checking the discharge, the pressure of the fluid supplied to the motor is increased and the power of the hydraulic motor correspondingly increased. In this connection it is'of interest that the'seat 13 is connected to the passage 2| at a point between the pressure side of the pump or other source of hydraulic fluid under pressure and the throttle 21. throttling member in the normal operation of the pump effects a reduction ofthe difference in.

pressure between thepressure passage 2| and the valve chamber 22, from which latter the hydraulic fluid passes to the hydraulic motor, it being. further of interest that the adjustability of the throttle opening through the-seat 26 is not essentialto the functioning of the relief valve in accordance with the invention, but such adjustability is desirable in the operation of the hydraulic motor under any circumstances.

lit'is the object of the invention, as already pointed out, to cause the hydraulic motor to operate under normal loads with the'minimum of power, utilizing 'a portion of the hydraulic fluid vpumped at a low pressure, the remainder of the fluid being discharged from' the pressure passage between the pump'delivery and the throttie, and preferably bypassed around the throttle This from the pressure to the suction side of the pump. As an excess resistance is encountered at the ram, it is the purpose of the invention to check the discharge of the fluid at the relief valve 88 whereby the pressure in the hydraulic fluid on the pressure side of the pump, i. e., in the passage 2 I, is built up, communicating the increased pressure through the throttle opening to the chamber 22 on the intake side of the hydraulic motor. To accomplish this result, an increased closing tendency is imparted to the relief valve member I4. This increased closing tendency is effected in accordance with the preferred form of the invention by means of a release valve piston 85 mounted in the release valve cylinder 86, see Figure 2, and fitting said cylinder to slide therein in response to hydraulic pressures set up in the cylinder or other convenient type of ex- ,pansible chamber similarly connected. Beneath the piston 85 and opposed to the expansion .of

the space between the piston and head I88, we

have shown a coil spring 8! engaging. the piston at one end and at the other end engaging the bottom of a cylindrical spring housing 88 which surrounds the spring. This housing 88 projects into the pump intake or suction chamber 28 and is vented into this chamber at 88, the cylinder 86 being formed in the opposite end of the casing 88, and also shown as projecting into chamber 28. The piston 85 as shown slides on the pin 82 as to which it serves as a gu de and by which it is partially guided. As shown, the piston is provided with a short tubular shank or piston rod 88 which extends to the right in the direction of the valve 14,,provided with an internal slide bearing 81, in which the pin 82 has a sliding fit. The bearing also extends through the piston proper as shown. -The pin 82 slides in the piston 85 and bearing 9| and the piston 85 moves on the pin, being also guided and supported in the cylinder.

The casing 88 including the cylinder 86 in the form shown extends through the wall of the chamber 28 and fits therein, being secured to said wall from without by a flange I85 formed,

on cylinder 86, which flange immediately overlies and fits closely to the wall, being held by screw bolts I86. The spring casing I6 which is shown as integral with the relief valve seat II, extends into the spring casing 88 through an opening I8I in the end wall of the casing and the adjusting screw 83 is seated in a piston head I88 which closes the end of the release valve cylinder 86, the head where it bears against flange I85 on i which it is seated, being suitably packed. It is held by screw bolts I88. The adjusting screw 83 is threaded into a boss I I8 formed on the cylinder head I88 and as shown it is protected by a cup III threaded on to the outer end of the boss H8.

The release valve cylinder 86 is connected by a passage 82 and 82' to the hydraulic motor valve chamber 22, i. e., between the hydraulic motor intake and throttle valve seat 26, which, as already pointed out, contains the throttled. hydraulic fluid under the pressure at which it is presented to the hydraulic motor. Inserted in this passage 82 between the cylinder 86 and chamber 22 is a check valve assembly 83 having a casing 84 which is shown as formed in two parts 84, 84", having a threaded engagement with each other; between the parts 84' and 84" is clamped a valve seat 85 having two ports 86, 81 extending therethrough, both connected by said casing as to their opposite openings to the two ends of the passage 82, 82', on the two sides of the valve casing 84. Cooperating with one of these ports is a check valve 81' shown as in the form of a ball valve held normally in contact with its seat by a coil spring 88, the valve being engaged with the side of the seat toward the cylinder86. The chamber 88 within the casing 84 is divided into two parts by a partition I88, and the half of the chamber on the right side in Figure 2 opposite the side containing valve 81' is closed at its upper end by a ball valve I 8| cooperating with a valve seat member or block I82 containing a passage with a valve seat I83 disposed toward the passage 82' adjacent the chamber 22 and held normally in contact with its seat by a coil spring I84. The presence of the valve assembly 83 in the passage 82, 82 is not absolutely essential to the operation of the relief valve or to the control of its operation by the piston 85 in the cylinder 86 but it is of great advantage in preventing frequent operation of the piston to increase the closing tendency of the valve I4 and thus build up the pressure in the passage 2I and the chamber 22 in response to minor changes of load where such increased pressure is not necessary to operate the ram with reasonable uniformity of speed. Frequent operation involves frequent vibrations-or reciprocations of the piston 85 and frequent flexing of the springs 81 and 11 which may be broken, and it also results in loss of power. The valve assembly 83 is instrumental, as already suggested, in preventing unnecessary and too frequent operations of the piston 85 with the consequent increased closing tendency of the valve I4 and building up of motor fluid pressure. It will be noted that the piston 85 which is an unbalanced piston receiving fluid pressure on one side only is of considerable area compared to the area of the valve seat I3 and also of the valve seat or port 88. The valve assembly 93 has the effect of protecting the piston 85 from frequent and relatively slight changes of fluid pressure in valve chamber 22 and also serves to release the excess pressure from the cylinder 86 when the excess load on the motor has ceased so that the back pressure on the motor fluid supply drops and the pump pressure is correspondingly reduced, thus permitting opening of the check valve I4 with further reduction of pump pressure as soon as the excess load on the motor is, disposed of.

In operation, when pressure in excess of the normal working pressure, is built up in chamber 22 due to increased'load on the hydraulic motor and consequently slower operation of 4 the hydraulic motor, this increased pressure is applied to the piston 85 by introduction of hydraulic fluid under pressure through the passage 82 from chamber 22 with or without check valve 83 into the cylinder 86; the piston 85 moves to the right against the tension of the spring 81 which has I previously balanced the pressure in the cylinder 86 due to normal pressure in chamber 22, and when the lost motion at I I2 has been taken up by compression of the spring 81, providing a time element in which valve I4 remains open as previously, due to the pressure in passage 2| on the pump side of the throttle opening, the relief valve spring 11 is compressed increasing the tension of the spring and the tendency to close the relief valve by advancing the ball valve I4 toward or against the seat I3. This increases the back pressure on the pump throwing an increased load on the electric motor I which in response increases the generation of power continuing the operation of the pump at the increased pressure, thus communicating increased pressure through the throttle 26, 21 to the cylinder valve chamber 22, from which the hydraulic fluid under infuel, or unusual coking or the like or in any way, as already described, causing excess resistance to thereciprocation of the ram and conse'. quent resistance to the advance of the hydraulic motor piston, the pressure in the chamber 22 of the piston valve being built up and increased as described, this pressure is'communicated from the hydraulic motor valve chamber 22 through passage 92 to the casing 94 of the checkvalve assembly and hence through the port 96 to the 9B and by normal pressure inthe chamber 86 communicated through passage 92 to the top of valve 91. The small area of the valve 91 which is exposed at the seat or port 96, so reduces the actualupward thrust applied to the ball by the increased pressure communicated from the chamber 22 that a considerable increase of pressure is'balanced by the spring 98 and a consequently considerable increase in pressure is necessary to open the valve 91. This prevents operation of the piston 85 on slight variations of load which occur frequently in the normal operation of the fuel feed and are overcome WiiLhL it the necessity for building up the pressure by closing the relief valve. In this way frequent reciprocations of the piston 85 with a consequent repeated flexing of the springs 81, TI and a resulting early breaking or deterioration of these springs is prevented. Also, frequent increases of load on the electric motor when such increase is unnecessary are prevented.

On the opening of the valve 91 the increased pressure from the chamber 22 is communicated through passage 92, the seat or port t6 and the passage 92'to the cylinder Bit-moving the pis ton 85 to the right, the transfer of fluid from the chamber 22 to the cylinder 86 continuing with a consequent advance of the piston 85 to the right until the lost motion at H2 is taken up and further continuing until the spring 11 is compressed, placing increased pressure on the valve \14 and either closing it or partially closing sage 2! is so increased as to communicate I through the throttle. 2B, 21 andto the chamber 22 sufficient increased pressure .to build up the power of the hydraulic motor to an extent which will cause it to overcome the increased load generally in the form of-an obstacle interposed in the path of the ram, as already described. When this excess resistance load has been overcome, the increased speed of the hydraulic motor causes a reduction of pressure in the chamber 22 and a reduction of pressure onthe under sideof the valve 91 which permits this'valve to close, and the reduction of pressure in chamber 22 and in the passage 92 resulting from the increased speed of the motor causes suflicient drop of pressure in the portion of the passage 92 adjacent k the chamber 22 and beneath the valve lfll so that this valve is unseated due to the excess pressure in the cylinder 86 whereby the excess fluid therefrom is permitted to escape past the rain under normal conditions at low pressures 'matically increasing the power. to overcome any seat I03 of the valve Illl returning to the chain-- ber 22 of the .piston valve, the fluid being expelled from the cylinder 88 by-the operation of the spring 81 until the pressure in the cylinder 86 is returned practically to normal and serves 5 to balance the spring 81, the piston 85 being then retired to the position, Figure 2. In this' way the excess pressure is removed from the spring "II, the relief valve 14 is opened by the pressure in passage I2 to a position in which the spring 11 balances the pressure against the ball 14 and operation of the hydraulic motor or pump continues at normal pressure and normal power, the excess fluid from the pump being by-passed from the pressure passage 2| connected to the delivery of the pump through the passage l2 and seat 13 to chamber 20 on the suction side of the pump or otherwise disposedof.

In this way the construction described provides for the bypaming of the hydraulic 'fiuid from the delivery or pressure side of the valve 91 which is held on its seat by the spring sure of thepump as just described, permitting the pump and motor to operate normally at a relatively low pressure and low consumption of power, the invention providing means whereby the tendency of the relief valveto close is increased whenever an increased load is communicated to the hydraulic motor by the ram, or otherwise encountered. This increased closing tendency is communicated to the relief valve it from a point in the hydraulic fluid pressure supplypassage or pressure passage leading from the pressure side of the pump to the intake of the motor, said point being preferably located between the throttle opening 26 or any throttling means and the intake of the motor in the form. shown from valve chamber 22, said increase of the closing tendency being further controlled by the check valve 91 'or equivalent means, means also being provided shownin the form of valve IIJI, for thereafter relieving the pressure set up in cylinder 86 or other expanding chamber in increasing the closing tendency'applied to the relief valve 14. I

Applicants have thus provided means for operating the hydraulic motor'which drives the with a minimum consumption of power autoobstacle which may be, encountered whenever such obstacles are encountered, also immediately reducing the power generated to normal when such obstacles have been overcome.

We have thus described specifically and in detail a hydraulic motor control for. use in connection with a fuel feed ram or the like, embody ing the features of our invention in the preferred form, in order that'the manner of constructin applying, operating and using the same maybe fully understood, however, the specific terms herein are used descriptively rather than in a limiting sense, the scope of the invention being defined in the claims.

What we claim as new and desire to secure by Letters Patent is:

1. The combination with a hydraulic motor and a fuel feed ram operated by the motor, a 75 p pump with a pressure passage connecting the pump to the hydraulic motor to supply fluid under pressure to the hydraulic motor to operate the motor, a source of power with a driving connection to the pump, of means in the pressure passage intermediate the pump and the motor intake for checking and determining the flow of fluid under pressure from said pump to the motor intake and effecting a drop of pressure in the fluid as fed to the motor intake when operating at normal speed, a relief valve connected to said passage between the pump and said checking means to discharge fluid therefrom, means tending to close said valve which is normally balanced by the fluid pressure holding the valve open to release a portion of the fluid pumped, permitting the pump and motor to operate under normal motor loads at a relatively low pressure, means connected to said motor supply pressure passage between said check and the motor and operated by the fluid pressure at that point for increasing the closing tendency of the release valve under loads in excess of the normal load as when excess resistance is encountered to the operation of the ram, tending to build up the operating pressure of the hydraulic motor.

2. The combination with a hydraulic motor and a fuel feed ram operated by the motor, and a pump with a pressure passage connecting the pump to. the hydraulic motor to supply fluid under pressure to the hydraulic motor to operate the motor, a source of power having a driving connection to the pump to operate the pump, the said pressure passage having means therein intermediate the pump and the motor for checking and determining the flow of fluid under pressure to the motor and effecting a drop of pressure beyond the check under normal loads and speeds, of a relief valve connected to said passage between the pump and said check, a spring tending to close said valve which is normally balanced by the fluid pressure holding the valve open to release a portion of the fluid pumped, permitting the pump and motor to operate under normal motor loads at a comparatively low pressure, means operated by the fluid pressure beyond the check for increasing the closing tendency of the release valve when excess resistance is encountered to the operation of the ram, increasing the motor load above normal and tending to decrease the speed of the motor and to build up the pressure beyond the check, said latter means including a cylinder, a piston therein connected to the spring and a fluid passage connecting said cylinder to the pressure passage between the check and the hydraulic motor to supply fluid to the cylinder to compress said spring, increasing the closing tendency of the valve and the pressure of the fluid delivered to the motor.

3. The combination with a hydraulic motor and a fuel feed ram operated by the motor, a pump with a pressure passage connecting the pump to the hydraulic motor to supply fluid under pressure to the hydraulic motor to operate the motor, a source of power with a driving connection to the pump, the said pressure passage tion of the fluid pumped, permitting the pump and motor to operate under said normal motor loads and speeds at a comparatively low pressure, means operated by the fluid pressure beyond the check for increasing the closing tendency of the release valve when excess resistance is encountered to the operation of the ram increasing the motor load above normal and building up the pressure beyond the check, said latter means including a cylinder, a piston therein and a fluid passage connecting said cylinder to the pressure passage between the check and the hydraulic motor, a spring applied to the piston oppositely to said pressure, a check valve in said latter passage opening toward the cylinder and a spring tending to maintain the check valve closed to prevent the communication through said passage to the cylinder of slight changes of pump pressure, and means for releasing fluid from said cylinder when the motor load and intake pressure are reduced to normal after such increased load.

4. The combination with a hydraulic motor and a fuel feed ram operated by the motor, a pump with a pressure passage connecting thepump to the hydraulic motor to supply fluid under pressure to the hydraulic motor to operate the motor, a source of power with a driving connection to the pump, the said pressure passage having means therein intermediate the pump and the motor for checking and determining the flow of fluid under pressure to the motor and effecting a drop of pressure beyond said check by means under normal loads and speeds, of a relief valve connected to said passage between the pump and said check, means tending to close said valve which is normally balanced by the fluid pressure holding the valve open to release a portion of the fluid pumped, permitting the pump and motor to operate under said normal motor loads and speeds at a comparatively low pressure, means operated by the fluid pressure beyond the check for increasing the closing tendency of the release valve when excess resistance is encountered to the operation of the ram, increasing the motor load above normal and building up the pressure beyond the check, said latter means including a cylinder, a piston therein and a fluid passage connecting said cylinder to the pressure passage between the check and the hydraulic motor, means tending to move the piston in opposition to the fluid pressure from said fluid passage, a check valve in said latter passage opening toward the cylinder and a spring tending to maintain the check valve closed to prevent the communication through said passage to the cylinder of slight changes of pump pressure, a closed passage connecting the motor discharge to the intake of the pump providing continuous circulation of the hydraulic fluid and the relief valve being connected to discharge into said latter passage, and means for releasing fluid from said cylinder when the motor load and intake pressure are reduced to normal after such increased load.

5. The combination with a hydraulic motor, a fuel feeding ram connected thereto to be operated thereby, the motor having valve means connected to the ram whereby the operation of the motor is controlled by the ram, a pump with a pressure passage connected to the pump discharge and to the intake of the hydraulic motor to supply the fluid under pressure to the intake of the hydraulic motor to operate the motor, power means for driving the pump and throttling means control- 5 ling the pressure passage between the pump and aovaisa r l the intakeof the hydraulic motor, of a relief valve connected to the pressure passage between the pump'and said throttling means, the relief valve being normally open to release a portion of the "fluid pumped whereby the pump and motor are normally ope'ratedat relatively low pressure, and

means connected to, the pressure passage between ing continuous circulation of the hydraulicfluid from the pump to the motor, said relief valve being connected to discharge into said latter passage.

6. The combination with a hydraulic motor, a

fuel feeding ram operated thereby, the motor having valve means connected to the ram whereby the operation of the motor is controlled by the ram, of apump having a pressure passageconneoting the pump delivery to the intake of the hydraulic motor leading fluid under pressure to the motor to operate the motor, means for driving the pump, and pressure reducing means in said passage between the pump and the motor of a relief valve connected to the pressure passage between the pump and saidfpressure reducing means, means tending to close the'relief valve against the pressure in said passage, said relief valve being held open by normal pressure to re-,,

lease a portion of the fluid pumped, causing the pump and motor to operate normally at a relatively low prgssure, means for increasing the tendency of said means to close the relief valve'comprising an expanding chamber having a moving member, said closing means comprising a spring and a lost motion device whereby said moving member is connected to the valve to increase the tendency to close the valve as said chamber expands beyond a predetermined point, a connection from said pressure passage, at a point be-- tween the pressure reducing means and the motor intake, to said expanding chamber to communicate the changesof pressure from said point to the expanding chamber whereby the tendency to close the relief valve is increased as the load on the mptor is increased beyond a predetermined point incident to increaseof resistance to the operation of the ram and means for releasing the pressure from said chamber when the pump intake pressure is reduced to normal.

7. The combination with a hydraulic motor, a fuel feeding ram operated thereby of a pump having a pressure passage connecting the" pump delivery to the intake of the hydraulic motor leading .fluid under pressure to the motor to operate the motor, means for driving the pump, and pressure reducing means in said passage between the pump and the motor, a relief valve connected to the pressure passage between the pump and said pressure reducing means, a spring tending to close the relief valve'against the pressure in said passage, said relief valve being held open by normal 7 pressure to release a portion of the fluid pumped, causing the pump and motor to operate normallyat a relatively lowpressure, means for increasingthe tendency of said spring to close the relief valve comprising an expanding chamber having a moving member, a lost motion device connected to said member, supporting saidspring oppositely to.-the valve toincrease the tendency to close the valve as said chamber expands, a spring tending-to contract said chamber, a connection from said pressure passage at a point bea fuel feeding ram operated thereby, a pump having a pressure passage connecting the pump delivery to the intake of the hydraulic motor leading fluid under pressure to the motor to operate the motor, means for driving the pump, and pressurereducing means insaid passage between the pump and the motor, of a relief valve connected to the pressure passage between the pump and said pressure reducing means, resilient means tending to close the relief valve against the pressure in said passage, saidresilient means being balanced and the relief valve being held open by n'ormal pressure to release a portion of the fluid pumped, causing the pump and motor to operate normally at relatively low pressure, means for increasing the tendency of said resilient means to close the relief valve comprising an expanding chamber having a resiliently controlled moving wall member, a lost motion device for transmitting pressure from said member to said relief valve by way of said resilient means in ,the direction of closing after a predetermined mofrom said point to the expanding chamber whereby the tendency to close the relief valve is increased as the load on the motor incident to increase of resistance to the operationof the ram is encountered, and means in said connection for 1 checking communication of slight changes of pressure from said pressure passage to said ex panding chamber.

9. The combination with a hydraulic motor, a fuel feeding ram operated thereby, a pump having a pressure passage connecting the pump delivery to the intake of the hydraulic motor leading fluid under pressure to the motor to operate the motor, means for driving the pump, and pressure. reducing means in said passage between the, pump and the-motor, of a relief valve connected-to the pressure passage between the pump and said pressure reducing means, resilient means tending to close the relief valve against the pressure in said passage, said resilient means being balanced and the relief valve being held open by normal pressure to release a portion of the fluid pumped, causing the pump and motor to operate normally at relatively low pressure, means for increasing the tendency of said resilient means to close the relief valve comprising an expanding v chamber having a moving wall member for transmitting increasedpressure through said resilient means to said relief valve in the direction of closing, a connection from said passage at a point between the pressure reducing means and the motor intake to said expanding chamber to communicatethe changes of pressure from said point to the expanding chamber whereby the tendency to close the relief valve is increased as the'load on the motor incident to increase of resistance to the operation of the ram is encountered, means tending to contract said chamber, a valve in said connection for checking communication of slight changes of pressure from said pressure passage to said expanding chamber, and a bypass with valve means therein providing for release of fluid from said chamber at a predetermined drop of the pump intake pressure, a passage connecting the motor exhaust to the intake of the pump providing continuous circulation of the hydraulic fluid, said relief valve being connected to discharge into said passage.

10. The combination with a hydraulic motor, a fuel feeding ram operated thereby, a pump having a pressure passage connecting the pump delivery to the intake of the hydraulic motor, leading fluid under pressure to the motor to operate the motor, and means for driving the pump, of flow retarding pressure reducing means in said passage between the pump and the motor, a relief valve discharging from the pressure passage between the pump and said pressure reducing means, means for closing the relief valve comprising an expanding chamber having a moving wall member and resilient means for transmitting pressure from said member to said valve tending to close the same, a connection from said motor pressure passage to said expanding chamber to communicate the changes of pressure from said motor to the expanding chamber whereby the relief valve is closed as an increased load on the motor incident to increase of resistance to the operation of the ram is encountered.

11. The combination with ahydraulic motor adapted to be directly connected to a fuel feeding ram to operate the same, to pump supplying hydraulic fluid under pressure to the motor, power means for operating the pump, said connection being in the form of a pressure passage connected to the delivery side of the pump and to the intake side of the motor, throttling means in said passage for checking the flow of hydraulic fluid eflecting a drop of pressure between the pump delivery and the motor intake at normal motor speeds and loads, and a passage-connecting the motor exhaust to the intake of the pump, said passage comprising a suction chamber of a relief valve seat connected to said pressure passage between the throttling means and the pump and having a discharge opening into said chamber, a

valve co-operating with said seat and closing against the pressure in the pressure passage, 2. spring tending to close the valve, the valve being balanced by normal pressure in the pressure passage so that the valve is normally open to bypass a portion of the fluid pumped from the pressure passage to said chamber, a cylinder, a spring'guide in alignment with said cylinder and forming an extension of said cylinder and also having its axis'in alignment with the axis of the valve seat and having a spring support at the end remote from the cylinder, a piston in said cylinder, a spring bearing at one end against said creased pressure to the valve spring and increasing the closing tendency of the relief valve, and a passage connected to the cylinder on the side of the piston remote from said valve and to the pressure passage between the throttling means and the motor intake.

12. The combination with a hydraulic motor adapted to be directly connected to a fuel feeding ram to operate the same, a pump supplying hydraulic fluid under pressure to the motor, power means for operating the pump, a pressure passage connected to the delivery side of the pump means in said passage for checking the flow of hydraulic fluid effecting a drop of pressure between the pump delivery and the motor intake at normal motor speeds and loans and a passage connecting the motor exhaust to the intake of the pump, said passage comprising a suction chamber, a relief valve seat connected to said pressure passage between the throttling means and the pump and having a discharge opening into said chamber, a valve cooperating with said seat and closing against the pressure in the pressure passage, a spring tending to close the valve balanced by normal pressure in the pressure passage so that the valve is normally open to bypass a portion of the fluid pumped from the pressure passage to said chamber, a cylinder, a spring guide in alignment with said. cylinder, forming an extension of said cylinder in the direction of the valve seat and also having its axis in alignment with the axis of the valve seat and having a spring support at the end remote from the cylinder, a piston in said cylinder, a spring bearing at one end against said piston and at the other end against said spring support, the cylinder being vented into said chamber, a plunger mounted to slide in alignment with the cylinder axis and bearing on the valve spring oppositely to the valve, means for applying the thrust of the,

piston to said plunger to increase the spring pressure tending to close the valve, the advance of the piston in response to the introduction of pressure into the cylinder applying increased pressure to the valve spring and increasing the closing tendency of the relief valve, said means having a clearance providing lost motion between the piston and the plunger before the pressure of the piston is applied to the plunger as the piston advanced,apassage connected to the cylinand to the intake side of the motor, throttling der on the side of the piston remote from said valve and to the pressure passage between the throttling means and the motor intake.

13. The combination with a hydraulic motor adapted to be directly connected to a fuel feeding ram to operate the same, a pump supplying hydraulic fluid under pressure to the motor, power means for operating the pump, a pressure passage connected to the delivery, side of the pump and to the intake side of the motor, throttle means in said passage for checking the flow of hydraulic fluid effecting a drop of pressure between the pump-delivery and the motor intake at normal motor speeds and loads and a passage connecting the motor exhaust to the intake of the pump," said passage comprising a suction chamber, a relief valve seat connected to said pressure passage between the throttling means and the pump and having a discharge opening into said chamber, a. valve cooperating with said seat and closing against the pressure in the pressure passage, a spring tending to close the valve, said spring being balanced by normal pressure in the pressure passage, so that the valve is nor mally open to bypass a. portion of the fluid pumped from the pressure passage to said chamber, a cylinder, a spring guide inalignment with said cylinder and forming an extension of said cylinder and also having its axis in alignment with the axis of the valve seat and having a spring support at the end remote from the cylinder, a piston in said cylinder, a spring hearing at one end against said piston and at the other end against said spring support, the cylinder being vented into said chamber, a plunger mounted to slide in the direction of the cylinder axis and bearing on the valve spring oppositely to the valve, means for applying the thrust of the piston to said plunger to increase thespring pressure tending to close the valve, the advance of the piston in response to the introduction of pressure into the cylinder applying increased pressure to the valve spring and increasing the closing tendency of the relief valve, said means having a clearance providing lost motion between the piston and the plunger with an interval after the initial motion of the piston and before the pressure of the piston is applied to the plunger, a passage connected to the cylinder on the side of the piston remote from said valve and to the pressure passage between the throttling means and the motor intake, a check valve in said passage o'pening toward the cylinder and means tending to maintain said valve closed whereby slight variations of pressure at the motor intake are overcome, without transmitting any additional fluid from the cylinder thus checking the I tendency to frequent-vibrations of the piston in response to minor changes of load but opening to communicate to the cylinder important changes of pressure at the motor intake which must be overcome by increased pressure in the hydraulic fluid and increased power and means for releasing fluid from the cylinder when increases of load have been overcome and the load and fluid pressure at the motor intake are reduced.

7 ing into said chamber, a valve cooperating with said seat closing against the pressure in said pressure passage, a spring tending to hold the valve closed, a guide for the spring connected to the valve seat, a cylinder, a spring support connected to said cylinder and located in the said chamber, said support having an opening in which the spring guide is located, a piston in said cylinder, the spring guide being. in alignment with the axis of the cylinder, a coil spr-Lng bearing at one end on the spring support and at the other end against the piston on the side toward the relief valve, 9. plunger engaging the valve spring oppositely to the valve, means for communicating the motion of the piston to the plunger, a passage connecting the cylinder on the side of the piston opposite to the valve to the pressure passage between the throttling means and the motor intake, means for adjusting the position of plunger and the tension of the valve spring, the connecting passage to the cylinder having a check valve therein which closes against the pressure from said pressure passa e, a spring tending to close said valve and a bypass around said valve, a valve in said bypass openingagainst the pressure in the pressure passage,-and means tending to maintain said latter valve on its seat, the first mentioned valve in said connecting passage serving to prevent the transmission to the cylinder of small fluctuations of load and pressure, but serving to open in response to larger fluctuations, the valve in the bypass being held closed by the increased pressure from the pressure passage, but being opened after each increased load has been overcome to release the excess pressure in the said cylinder and permit the cylinder to be returned to its normal position by the operation of the spring which bears on the piston.

15. The combination with a hydraulic motor and a pump for supplying fluid to the same to operate the motor, of a low pressure fluid supply chamber for the pump to which the motor discharge is connected, a pressure passage connected -to the pump delivery and to the motor to operate the same, a throttle in said passage, a

relief valve located in the supply chamber and connected to said pressure passage between thepump and the throttle to discharge from said passage into the supply chamber, a spring tending to close said valve, a cylinder in substantial alignment with said valve and spring, a piston sure to said spring to increasethe closing tendency of said, valve, a second spring bearing on said piston'in opposition to the pressure thus applied to the valve and a passage connected to said cylinder and to said pressure passage between the throttle and the motor intake for increasing the pressure on the valve spring as the pressure of the fluid supply to the motor is increased to a point where it moves the piston in opposition to said second spring. e

16. The combination with a hydraulic motor and a pump for supplying fluid to the same to operate the motor, of a low pressure fluid supply chamber for the pump to which the motor discharge is connected, a pressure passage connected to the pump delivery and to the motor to operate the same, a throttle in said passage, a

relief valve connected to the supply chamber and connected to said pressure passage between the pump and the throttle to discharge from said passage into the supply chamber, a spring tending to close said valve, a cylinder in substantial alignment with said valve and spring, a piston in said cylinder and a lost motion device connecting the piston to the spring for applying pressure to said spring to increase the closing tendency of said valve, 2. second spring bearing on said piston in opposition to the pressure thus applied to the valve and a passage connected to said cylinder and to said pressure passage between the throttle and the motor intake for increasing the pressure on the valve spring as the pressure of the fluid supply to the motor is increased to a point where it moves the piston in opposition to said second spring, said latter passage having a bypass andtwo oppositely operatingflow check means in parallel in said passage and bypass respectively to limit the operation of the piston to predetermined high and low pressures.

17. The combination witha' hydraulic motor and a pump for supplying fluid to the same to chamber for the pump to which the motor discharge is connected, a pressure passage connected to the pump delivery and to'the motor to operate the same, a throttle in said passage, a relief valve'located in the supply chamber and connected to said pressure passage between the pump and the throttle to discharge from said passage into the supply chamber, a spring tending to close said valve, a cylinder in substantial alignment with said valve and spring, a piston in said cylinder and means connecting the piston to the spring for applying pressure to said spring to increase the closing tendency of said valve, a second spring bearing on 'said piston in opposition to the pressure thus applied to the valve and a passage connected to said cylinder and to said pressure passage between the throttle and the motor intake for increasing the pressure on the valve spring as the pressure of the fluid supply to the motor is increased to a point where it moves the piston in opposition to said second spring, and means externally located as to said supply chamber for adjusting the tension of the valve spring, said means extending through said piston.

18. The combination witha hydraulic motor and a fuel feed ram operated by the motor oi? a supply of fluid under pressure and a passage connecting said supply to the hydraulic motor intake to supply fluid under pressure thereto to operate the motor, means in said pressure passage adjacent the motor intake for checking. and determining the flow of fluid under pressure from said supply to the motor intake, effecting a drop of pressure in the fluid as fed. to the motor when operating at normal speed, a relief valve connectoperate the motor, of a low pressure fluid supply ed to said passage between the pump and said check, means tending to close said valve, which is normally balanced by the fluid supply pressure holding the valve open to release a portion of the fluid, permitting the motor to operate under normal loads at a relatively low pressure, means connectedto said motor supply pressure between said check and the motor intake and operated by the fluid pressure at that point for increasing the closing tendency of the relief valve under loads in excess of the normal load as when excess resistance is encountered to the operation of the ram, thereby tending to build up the operating pressure of the hydraulic motor.

19. ,The combination with a hydraulic cylinder of a fuel feeding ram operated thereby, a pump having a pressure passage connecting the delivery of the pump to the hydraulic cylinder intake andan electric motor driving the pump, of flow retarding pressure reducing means in said passage between the motor and the pump, a normally open relief valve discharging from said passage between the pump delivery and the pressure reducing means, a hydraulic chamber having a moving wall member, a passage connecting said chamber to the pressure passage beyond said reducing means, resilient means tending to close said relief valve, said resilient means being connected oppositely to said valve and to said moving wall member whereby the tendency to close said valve'is increased as the load on the hydraulic cylinder and hence the pressure in said chamber is increased.

JAMES F. TURNER. 

